Wool dryer balls work best on natural fibres, such as linen, cotton, hemp and bamboo. This is because synthetics cling and pull the wool fibres from the dryer balls, causing lint and in some cases static. This isn’t harmful but can reduce the lifespan of your Wool Dryer Balls.
In general, manufacturers recommend that synthetic products be hung to dry, as the heat from the dryer can break down the elasticity of non-natural fibres, decreasing their longevity. They also suggest this to eliminate pilling which can be caused during the drying cycle when tumbling with natural fibres.
We recommend you read each label as a surprising number of clothes contain non-natural or synthetic materials.
If you have blended fibre fabrics that are more of a natural fibre than not, you should not have a lint issue. But, if the fibre content is close to a 50/50 ratio, we recommend you hang dry your synthetics.